Gutters and down spouts present a troublesome problem. Should ice form in a gutter, there is a real threat that water will eventually back up under the shingles and leak into the building as snow accummulates in valleys and along the eaves with interior damage resulting. Even if such damage does not occur, an ice-full gutter will overflow to form icicles. Down spouts, while usually less troublesome, can lead to the gutter problems as they sometimes become ice blocked, usually at their lower ends where they are commonly angled away from the building. With some buildings, there may be freezing at their upper ends in the event the down spout has to be angled inwardly towards the side of the building.